I previously discussed the power of fruits and vegetables to help prevent and treat asthma and allergies. If adding a few more servings of fruits and vegetables may help asthma, what about a diet centered around plants? Twenty patients with allergic eczema were placed on a vegetarian diet. At the end of two months, their disease scores, which covered both subjective and objective signs and symptoms, were cut in half, similar to what we might see using one of our most powerful drugs. The drug works much quicker, within about two weeks, but since drugs can often include dangerous side effects the dietary option is more attractive. This was no ordinary vegetarian diet, however. This was an in-patient study using an extremely calorically-restricted diet--the subjects were practically half fasting. Therefore, we don't know which component was responsible for the therapeutic effect.

What about using a more conventional plant-based diet against a different allergic disease, asthma? In Sweden, there was an active health movement that claimed that a vegan diet could improve or cure asthma. This was a bold claim, so in order to test this, a group of orthopedic surgeons at Linköping University Hospital followed a series of patients who were treated with a vegan regimen for one year. (This study is highlighted in my video, Treating Asthma and Eczema with Plant-Based Diets.) Participants had to be willing to go completely plant-based, and they had to have physician-verified asthma of at least a year's duration that wasn't getting better or was getting worse despite the best medical therapies available.

The researchers found quite a sick group to follow. The thirty-five patients had long-established, hospital-verified bronchial asthma for an average duration of a dozen years. Of the 35 patients, 20 had been admitted to the hospital for acute asthmatic attacks during the last two years. Of these, one patient had received acute infusion therapy (emergency IV drugs) a total of 23 times during this period and another patient claimed he had been to the hospital 100 times during his disease and on every occasion had evidently required such treatments. One patient even had a cardiac arrest during an asthma attack and had been brought back to life on a ventilator. These were some pretty serious cases.

The patients were on up to eight different asthma medicines when they started, with an average of four and a half drugs, and were still not getting better. Twenty of the 35 were constantly using cortisone, which is a powerful steroid used in serious cases. These were all fairly advanced cases of the disease, more severe than the vegan practitioners were used to.

Eleven couldn't stick to the diet for a year, but of the 24 that did, 71% reported improvement at four months and 92% at one year. These were folks that had not improved at all over the previous year. Concurrently with this improvement, the patients greatly reduced their consumption of medicine. Four had completely given up their medication altogether, and only two weren't able to at least drop their dose. They went from an average of 4.5 drugs down to 1.2, and some were able to get off cortisone.

Some subjects said that their improvement was so considerable they felt like "they had a new life." One nurse had difficulty at work because most of her co-workers were smokers, but after the plant-based regimen she could withstand the secondhand smoke without getting an attack and could tolerate other asthma triggers. Others reported the same thing. Whereas previously they could only live in a clean environment and felt more or less isolated in their homes, they could now go out without getting asthmatic attacks.

The researchers didn't find only subjective improvements. They also found a significant improvement in a number of clinical variables, most importantly in measures of lung function, vital capacity, forced expiratory volume, and physical working capacity, as well as significant drops in sed rate (a marker of inflammation) and IgE (allergy associated antibodies).

The study started out with 35 patients who had suffered from serious asthma for an average of 12 years, all receiving long-term medication, with 20 using cortisone, who were "subjected to vegan food for a year," and, in almost all cases, medication was withdrawn or reduced, and asthma symptoms were significantly reduced.

Despite the improved lung function tests and lab values, the placebo effect can't be discounted since there was no blinded control group. However, the nice thing about a healthy diet is that there are only good side effects. The subjects' cholesterol significantly improved, their blood pressures got better, and they lost 18 pounds. From a medical standpoint, I say why not give it a try?

If you missed the first three videos of this 4-part series here are the links:

I talk a lot about numbers and statistics, but as the Director of Yale's Prevention Research Center Dr. David Katz put it in an editorial in the American Journal of Health Promotion, to reach doctors, our fellow colleagues, maybe we need to "put a human face on it all."

We have known, for at least a decade that the "leading causes of both premature death and persistent misery in our society are chronic diseases that are, in turn, attributable to the use of our feet (exercise), forks (diet), and fingers (cigarette smoking). Feet, forks, and fingers are the master levels of medical destiny for not just thousands of people on any one occasion but the medical destiny of millions upon millions year after year."

We as doctors, as a medical profession have known--Ornish published his landmark study 25 years ago (See Our Number One Killer Can Be Stopped). "We have known, but we have not managed to care," writes Dr. Katz. "At least not care deeply enough to turn what we know into what we routinely do." Were we to do so, we might be able to eliminate most heart disease, strokes, diabetes, and cancer.

But saving millions of lives is just a number. He asks doctors to:

"forget the bland statistics of public health, and ask yourself if you love someone who has suffered a heart attack, stroke, cancer, or diabetes....Now imagine their faces, whisper their names. Recall what it felt like to get the news. And while at it, imagine the faces of others like you and me imagining beloved faces. Now imagine if eight out of ten of us wistfully reflecting on intimate love and loss, on personal anguish, never got that dreadful news because it never happened. Mom did not get cancer; dad did not have a heart attack; grandpa did not have a stroke; sister, brother, aunt, and uncle did not lose a limb or kidney or eyes to diabetes. We are all intimately linked, in a network of personal tragedy that need never have occurred."

Which leads to what he is asking doctors to do about it: put a face on public health every chance you get. "When talking about heart disease and its prevention--or cancer or diabetes--ask your audience to see in their mind's eye the face of a loved one affected by that condition. Then imagine that loved one among the 80% who need never have succumbed if what we knew as doctors were what we do."

Following flax and wheatgrass, turmeric is the third best-selling botanical dietary supplement, racking up $12 million in sales. Currently, sales are increasing at a rate of 20%.

"Curcumin is a natural plant product extracted from the turmeric root and is used commonly as a food additive popular for its pleasant mild aroma and exotic yellow color. It is widely considered unlikely to cause side effects." However, just because something is natural doesn't mean it's not toxic. Strychnine is natural; cyanide is natural. Lead, mercury and plutonium are all elements--can't get more natural than that! But turmeric is just a plant. Surely plants can't be dangerous? Tell that to Socrates.

"In considering the validity of the widely accepted notion that complementary and alternative medicine is a safer approach to therapy, we must remind ourselves and our patients that a therapy that exerts a biologic effect is, by definition, a drug and can have toxicity." It cannot be assumed that diet-derived agents will be innocuous when administered as pharmaceutical formulations at doses likely to exceed those consumed in the diet.

Traditional Indian diets may include as much as a teaspoon of turmeric a day. Doses of turmeric that have been used in human studies range from less than just a 16th of a teaspoon a day to two tablespoons a day for over a month. On the other hand, the curcumin trials have used up to the amount found in cups of the spice, around 100 times more than what curry lovers have been eating for centuries.

Studies have yet to show overt serious side effects in the short-term. However, if we combine high dose curcumin with black pepper, resulting in a 2000% boost in bioavailability (See Boosting the Bioavailability of Curcumin), it could be like consuming the equivalent of 29 cups of turmeric a day. That kind of intake could bring peak blood levels to the range where you start seeing some significant DNA damage in vitro.

So just incorporating turmeric into your cooking may be better than taking curcumin supplements, especially during pregnancy. The only other contraindication cited in the most recent review on curcumin was the potential to trigger gallbladder pain in individuals with gallstones.

If anything, curcumin may help protect liver function and help prevent gallstones by acting as a cholecystokinetic agent, meaning that it facilitates the pumping action of the gallbladder to keep the bile from stagnating. In one study, profiled in my video, Who Shouldn't Consume Turmeric or Curcmin?, researchers gave people a small dose of curcumin, about the amount found in a quarter teaspoon of turmeric and, using ultrasound, were able to visualize the gallbladder squeezing down in response, with an average change in volume of about 29%. Optimally, though we want to squeeze it in half. So the researchers repeated the experiment with different doses. It took about 40 milligrams to get a 50% contraction, or about a third of a teaspoon of turmeric every day.

On one hand that's great--totally doable. On the other hand, that's some incredibly powerful stuff! What if you had a gallbladder obstruction? What if you had a stone blocking your bile duct? If you eat something that makes your gallbladder squeeze so much, it could cause pain. So patients with biliary tract obstruction should be careful about consuming curcumin. For everyone else, these results suggest that curcumin can effectively "induce the gallbladder to empty and thereby reduce the risk of gallstone formation and ultimately even gallbladder cancer."

Too much turmeric, though, may increase the risk of kidney stones. As I mentioned in Oxalates in Cinnamon, turmeric is high in soluble oxalates which can bind to calcium and form insoluble calcium oxalate, which is responsible for approximately 75% of all kidney stones. "The consumption of even moderate amounts of turmeric would therefore not be recommended for people with a tendency to form kidney stones." Such folks should restrict the consumption of total dietary oxalate to less than 40 to 50 mg/day, which means no more than at most a teaspoon of turmeric. Those with gout, for example, are by definition, it appears, at high risk for kidney stones, and so if their doctor wanted to treat gout inflammation with high dose turmeric, he or she might consider curcumin supplements, because to reach high levels of curcumin in turmeric form would incur too much of an oxalate load.

If we are going to take a supplement, how do we choose? The latest review recommends purchasing from Western suppliers that follow recommended Good Manufacturing Practices, which may decrease the likelihood of buying an adulterated product.

A new study from China found that compared to omnivores, those who ate egg-free and meat-free diets had all the typical benefits of eating more plant-based: lower body mass index, lower blood pressure, lower triglyceride, lower total cholesterol, lower bad cholesterol, less free radical damage, etc. Having said that, if those on plant-based diets don't get enough vitamin B12, levels of an artery-damaging compound called homocysteine can start to rise in the bloodstream and may counteract some of the benefits of healthy eating.

In a study profiled in my video, Vitamin B12 Necessary for Arterial Health, a group of Taiwanese researchers found that the arteries of vegetarians were just as stiff as the omnivores and both had the same level of thickening in their carotid arteries, presumably because of the elevated homocysteine levels. The researchers concluded:

"The negative findings of these studies should not be considered as evidence of neutral cardiovascular effects of vegetarianism, but do indicate an urgent need for modification of vegan diets through vitamin B12 fortification or supplementation. Vitamin B12 deficiency is a very serious problem leading ultimately to anemia, neuropsychiatric disorders, irreversible nerve damage, and high levels of artery-damaging homocysteine in the blood. Prudent vegans should include sources of vitamin B12 in their diets."

One study of vegetarians whose B12 levels were really hurting found that they had even thicker, more dysfunctional arteries than omnivores. How do we know B12 was to blame? Because once they were given B12 supplements they got better. Their arterial lining started to shrink back, and the proper functioning of their arteries returned.

Without B12 fortified foods or B12 supplements, omnivores who were switched to a vegan diet developed vitamin B12 deficiency. Yes, it may take our blood levels dropping down to around 150 picomoles per liter to develop classic signs of B12 deficiency, like anemia or spinal cord degeneration, but way before that, we may start getting increased risk of cognitive deficits and brain shrinkage, stroke, depression, and nerve and bone damage. The rise in homocysteine may attenuate the beneficial effects of a vegetarian diet on cardiovascular health. The researchers concluded that while the beneficial effects of vegetarian diets on cholesterol and blood sugars "need to be advocated, but at the same time efforts to correct vitamin B12 deficiency in vegetarian diets can never be overestimated."

Type 2 diabetes is becoming a global pandemic. We know the consumption of eggs is related to the development of some other chronic diseases, what about diabetes? There appears to be a stepwise increase in risk as more and more eggs are consumed. One study found that eating just a single egg a week increased the odds of diabetes by 76%. Two eggs a week doubled the odds, and an egg a day tripled the odds.

Recent studies, profiled in my video Eggs and Diabetes, have confirmed the link. In 2009, Harvard researchers found that a single egg a day or more was associated with an increased risk of Type 2 diabetes in men and women. This finding has since been confirmed in Asia in 2011 and in Europe in 2012. Reducing egg consumption should start early in life, though, as it appears once we get into our 70s, it may be too late.

For those with diabetes, eggs may then hasten our death. Eating one egg or more a day appears to shorten anyone's lifespan, but may be even worse for those with diabetes, potentially doubling all-cause mortality, meaning egg-eating diabetics seem to live particularly short lives.

This is not good news for the egg industry. From a transcript of a closed meeting I got through the Freedom of Information Act, one egg industry advisor said, "Given the rate at which obesity and incidence of type II diabetes is growing in the US, any association between dietary cholesterol and type II diabetes could be a 'showstopper' that could overshadow the positive attributes in eggs."

More Freedom of Information Act insights into the egg industry can be found in:

In my video, Treating Kidney Failure Through Diet, I profiled research suggesting that the use of a plant-based diet for patients with kidney failure would be beneficial. An important function of our kidneys is to filter out excess phosphorus from our bloodstream, so a decline in kidney function can lead to the build-up of phosphorus in our bodies. This in turn can cause something called metastatic calcification, where our heart valves and muscles and other parts of the body can buildup mineral deposits, eventually potentially resulting in bad things like skin necrosis, gangrene, and amputations. Therefore, controlling dietary phosphorus intake is the lynchpin of successful prevention of metastatic calcification. While both plant foods and animal foods have phosphorus, our bodies seem better able to handle phosphorus excretion from plants, so a plant-based diet may help protect against this dreadful condition.

However, we're beginning to realize that absorbing too much phosphorus isn't good for anyone, even those with healthy kidneys. Having high levels in our blood has been found to be an independent predictor of heart attacks and mortality in the general population, increasing the risk not only of kidney failure, but also of heart failure, heart attacks, coronary death, and overall death. Dietary intake of phosphate is an important matter not just for persons with kidney disease, but for everybody. It's thought to cause damage to blood vessels, to accelerate the aging process, and even, potentially, to hurt our bones by contributing to osteoporosis via a disruption of hormonal regulation. The estimated average requirement of phosphorus is less than 600 mg a day, but the estimated average intake in the United States is nearly twice that. How do we stay away from too much of the stuff?

In the video, Phosphate Additives in Meat Purge and Cola, we can see the different levels of phosphorus in different foods. It looks like many plant foods have as much phosphorus as many animal foods. So why are plant-based diets so effective in treating kidney failure patients? Because most of the phosphorus in plant foods is found in the form of phytic acid, which we can't digest. Therefore, while plant and animal foods may have similar phosphate contents, the amount that is bioavailable differs. In plant foods, the bioavailability of phosphates is usually less than 50%, while the bioavailability of most animal products is up around 75%.

So when we adjust for how much actually gets into our system, plant foods are significantly better. It's like the absorption of heme and non-heme iron: our bodies can protect themselves from absorbing too much plant-based iron, but can't stop excess muscle and blood-based (heme) iron from animals slipping through the intestinal wall (see my video Risk Associated With Iron Supplements).

The worst kind of phosphorus is in the form of phosphate additives (which are absorbed nearly 100%) that are added, for example, to cola drinks. Why is phosphate added to cola? Without the added phosphate, so many glycotoxins would be produced that the beverage would turn pitch black (see my video on Glycotoxins). Thus, cola drinks owe their brown color to phosphate.

Phosphate additives play an especially important role in the meat industry, where they are used as preservatives for the same reason: to enhance a meat product's color. Just like the dairy industry adds aluminum to cheese, the meat and poultry industries "enhance" their products by injecting them with phosphates. If one looks at meat industry trade journals and can get past all the macabre ads for "head dropping robots for the kill floor," you'll see all ad after ad for injection machines. Why? Because of "increased profitability." Enhanced meats have better color and less "purge."

Purge is a term used to describe the liquid that seeps from flesh as it ages. Many consumers find this unattractive, so the industry views phosphate injection as a win-win. When chicken is injected with phosphates, the "consumer benefits through the perception of enhanced quality," and the processor benefits from increased yield because they just pump it up with water and they sell it by the pound. The problem is that it can boost phosphorus levels in meat nearly 70%, a "real and insidious danger" not only for kidney patients, but for us all.

In my video, Increased Lifespan From Beans, I discuss how beans may be the single most important dietary predictor of a long lifespan. But why do people who eat legumes such as beans, chickpeas, split peas, and lentils live longer? It may be because men and women who eat legumes have been shown to be lighter, have a slimmer waist, lower blood pressure, lower blood sugars, lower cholesterol, lower triglycerides, and better kidney function. Interestingly, bean intake is a better protector against mortality in women than in men. This may be because cancer--especially breast cancer--was the leading killer of women in the population studied.

Breast cancer survivors who eat soy foods, for example, have a significantly lower likelihood of cancer recurrence. A 2012 review looked at the three studies done to date on the link between soy and breast cancer survival. It showed that women who ate the most soy had a 29% lower risk of dying from breast cancer and a 36% lower risk of cancer recurrence. A fourth study has since been published that reaffirms these results. With an average intake of soy phytonutrients above 17 mg/day--the amount found in about a cup of soymilk--the mortality of breast cancer may be reduced by as much as 38%.

In my video, BRCA Breast Cancer Genes and Soy, you can see a five-year survival curve for Chinese women with breast cancer. After two years, all of the breast cancer survivors that ate lots of soy were still alive, while only about two-thirds of the women who ate the least amount of soy were alive. After five years, 90% of the tofu lovers were still alive and kicking, whereas half of the tofu haters had kicked the bucket. There is a similar relationship between breast cancer survival and soy protein intake, as opposed to just soy phytonutrient intake.

How does soy so dramatically decrease cancer risk and improve survival? Soy may actually help turn back on women's BRCA genes. BRCA is a so-called "caretaker gene," an oncosuppressor (cancer-suppressing) gene responsible for DNA repair. Mutations in this gene can cause a rare form of hereditary breast cancer, popularized by Angelina Jolie's public decision to undergo a preventive double mastectomy. But only about 5% of breast cancers run in families; 95% of breast cancer victims have fully functional BRCA genes. So if their DNA repair mechanisms are intact, how did breast cancer form, grow, and spread? It does so by suppressing the expression of the gene through a process called methylation. The gene's fine, but cancer found a way to turn it down or even off, potentially facilitating the metastatic spread of the tumor.

And that's where soy may come in.

The reason soy intake is associated with increased survival and decreased cancer recurrence may be because the phytonutrients in soy turn back on the BRCA protection, removing the methyl straightjacket the tumor tried to place on it. To find out if this is indeed the case, a group of researchers put it to the test.

In the video mentioned earlier, BRCA Breast Cancer Genes and Soy, you can see normal cells side-by-side with three different types of human breast cancer cells, specially stained so that the expression of BRCA genes shows up brown. Column 1 (far left) shows what fully functioning DNA repair looks like--what normal breast cells should look like--lots of brown, lots of BRCA expression. Column 2 shows raging breast cancer cells. If you add soy phytonutrients to the cancer (columns 3 and 4), the BRCA genes get turned back on and DNA repair appears to start ramping back up. Although this was at a pretty hefty dose (equivalent to about a cup of soybeans), the results suggest that treatment with soy phytonutrients might reverse DNA hypermethylation and restore the expression of the tumor suppressor genes BRCA1 and BRCA2. Soy appears to also help with other breast cancer genes as well, and women at increased genetic risk of breast cancer may especially benefit from high soy intake.

No matter what genes we inherit, changes in diet can affect DNA expression at a genetic level. No matter what bad genetic cards we've been dealt, we can reshuffle the deck with diet. For examples, see:

In my video Alkaline Diets, Animal Protein, and Calcium Loss I presented evidence challenging the notion that our body is buffering the acid formed from our diet with calcium from our bones. How then is our body neutralizing the acid? Maybe with our muscles! Our blood gets more acidic as we age and our kidney function declines, and this may be a reason we lose muscle mass as we get older. As a pair of researchers note: "The modern Western diet based on animal products generates an acid load that may cause a lifespan state of unnoticed and growing metabolic acidosis." This chronic low-level diet-dependent metabolic acidosis might contribute to the progressive shrinking of our muscle mass as we age.

Muscle wasting appears to be an adaptive response to acidosis. When our muscles break down, amino acids are released into the bloodstream. Our liver can then take these amino acids and make something called glutamine, which our kidneys can use to get rid of excess acid. And indeed, in a three year study I profile in my video, Testing Your Diet with Pee and Purple Cabbage, those over age 65 eating alkaline diets were better able to preserve their muscle mass, which the researchers think may be because the alkaline-producing fruits and vegetables helped relieve the mild acidosis that occurs with the ingestion of the standard American diet.

So what should we think about the latest review's question, "Does an alkaline diet benefit health?" If the question is "Does a diet low in meat, eggs, and dairy--all acid-producing--and high in fruits and vegetables with lots of dark green leafies benefit health?" then of course the answer is yes, an alkaline diet benefits health. But if the question is "Does it matter what our 'peeH' is (whether our urine is acid or alkaline) regardless of what actually goes into our mouth?" then the answer is... still yes, but the accepted benefits of having alkaline urine appear limited to two areas: lower risk of kidney stones and better uric acid clearance.

We've known about kidney stones and alkalinity for a while, but the uric acid data is new. Researchers have found that alkalization of the urine is effective for removing uric acid from the body. If you remember from my video Flesh and Fructose, uric acid is bad stuff (potentially increasing one's risk of fatal stroke, heart disease, and death), so clearing more from your system is a good thing.

Those eating plant-based diets appear then to have an advantage in this regard. The average vegetarian diet is alkaline producing, and the average meat-eating diet is acid producing. Even though there are some acid-forming meat-substitutes, like some of the Quorn products, they're not as bad as something like tuna, and they're typically consumed in smaller quantities than meat consumers consume meat. Since the protein in plants is usually accompanied by much more potassium (which is alkalinizing), there is good reason to try to meet protein needs from plant sources. And when researchers actually measure urine pH, those eating strictly plant-based diets have the greatest advantage, with significantly more alkaline urine than omnivores.

How can we tell what our urine pH is? Well we can be all boring and order some pH paper strips to pee on. Or... we can use what everyone should have right now in their crisper, a purple cabbage. Everyone should have a red or purple cabbage in their fridge since it is not only one of the single best nutrition bangs for our buck, but we can also do science with it!

First, either boil some purple cabbage until the water turns deep purple or (a quicker and safer way since there's no hot liquids) blend some raw with water in a blender and strain out the solids. Then what you can do with that royal purple liquid is pour it in the toilet bowl after you urinate. (You can imagine how much fun kids have with this!)

If it stays purple, your urine is acidic and you should eat more dark green leafy vegetables. If the toilet bowl turns pink, your urine is really acidic, so you should definitely eat more dark green leafy vegetables. We're looking for blue. If it turns blue that means your urine is neutral or even basic. If it's sky blue, you should... continue to eat more dark green leafy vegetables. Now I have a low-flow toilet, so there's very little water in the bowel to start with. The effect might not be as dramatic if diluted in a larger quantity of water. For a step-by-step tutorial, see my video Testing Your Diet with Pee & Purple Cabbage.

For most of the last century, a prevailing theory within the field of nutrition was that by eating acid-forming foods such as meat, we were, in essence, at risk of peeing our bones down the toilet. And no wonder! Experiments dating back to 1920 showed over and over that if we add meat to our diet we get a big spike in the amount of calcium being lost in the urine.

And this made total sense. We had known since 1912 that meat was acid-forming within the body, and how do we buffer acid? What are in antacid (anti-acid) pills like Tums? Calcium compounds.

Meat and eggs have a lot of sulphur-containing amino acids (two to five times more than grains and beans) that are metabolized into sulphuric acid, which the body buffers with calcium compounds. And where is calcium stored in the body? The skeleton. So the thinking was that every time we ate a steak, our body would pull calcium from our bones, bit by bit, and over time this could lead to osteoporosis. Based on 26 such studies, for every 40 grams of protein we add to our daily diet, we pee out an extra 50 mg of calcium. We only have about two pounds of calcium in our skeleton, so the loss of 50 grams a day would mean losing close to 2% of our bone calcium every year. By the end of the 20th century, there was little doubt that acid-forming diets would dissolve our bones away.

But if we actually look at the studies done on protein intake and bone health, that's not what we find. So, where's the flaw in the logic? Meat leads to acid, which leads to calcium loss, which leads to bone loss, right?

Well, it's uncontroversial that protein results in greater calcium excretion, but we've just been assuming it's coming from the bone--where else could the extra calcium dumped in our urine be coming from but our bones?

One study appeared to solve the mystery. An intrepid group of researchers tried feeding a group of volunteers radioactive calcium and then put them on a high protein diet. What happens when we put people on a high protein diet? The amount of calcium in their urine shoots up, and indeed that's just what happened. But here's the big question, was that extra calcium in their urine radioactive or not? To everyone's surprise, it was radioactive. This meant that the excess calcium in their urine was coming from their diet, not from their bones.

What seemed to be happening is that the excess protein consumption boosted calcium absorption, from down around 19% up to 26%. All of a sudden there was all this extra calcium in the blood, so presumably the kidneys are like "whoa, what are we going to do with it all?" So they dump it into the urine. 90% of the extra calcium in the urine after eating a steak doesn't appear to be coming from our bones but from our diet. We're not sure why protein boosts calcium absorption. Maybe protein increases the solubility of calcium by stimulating stomach acid production? Whatever the reason, there was indeed more calcium lost, but also more calcium gained such that in the end, most of that extra calcium is accounted for. In effect, more calcium is lost in the urine stream, but it may be compensated by less loss of calcium through the fecal stream.

This was repeated with even more extreme diets--an acid-forming five-burgers-a-day-worth-of-animal protein diet that limited fruits and vegetables versus an alkaline diet emphasizing fruits and vegetables. More calcium in the urine on burgers, but significantly greater calcium absorption, such that at the end it was pretty much a wash.

Other studies have also since supported this interpretation. Here's an ingenious one: Feed people a high animal protein diet but add in an alkali salt to neutralize the acid. The old thinking would predict that there would be no calcium loss since there is no excess acid to buffer, but no, even though the acid load was neutralized, there was still the excess urinary calcium, consistent with the radioactive isotope study, challenging the "long-standing dogma that animal protein consumption results in a mild acidosis promoting the increased excretion of calcium."

So if our body isn't buffering the acid formed from our diet with our bones, how is it neutralizing the acid? Maybe with our muscles. Alkaline diets may protect our muscle mass! I cover that in my video Testing Your Diet with Pee and Purple Cabbage.

Now the boost in calcium absorption can only compensate if we're taking enough in. For example, dietary acid load may be associated with lower bone mineral density in those getting under 800mg a day. Plant Protein is Preferable to animal protein for a variety of reasons (tends to have less methionine, is less IGF-1 promoting, etc.), but it's not clear how much of an advantage it has when it comes to bone health.

Note to chemistry geeks: Yes, I know it's the calcium salt anions that actually do the buffering (carbonate in Tums and phosphate in bones), but I'm trying my best to simplify for a largely lay audience. I'll make it up to you with some kitchen chemistry (actually bathroom chemistry!) in my Testing Your Diet video.